An outboard motor is mounted at the rear of the hull of a small-sized marine vessel. An outboard motor is provided with a horizontal, bar-shaped steering handle. Known examples of such outboard motors are disclosed in Japanese Patent Application Laid-Open Publication No. 2005-319881 (JP 2005-319881 A) and Japanese Patent Post-Exam Publication No. H02-014235 (JP H02-014235 B).
The outboard motors disclosed in JP 2005-319881 A and JP H02-014235 B have a rotatable grip at the distal end of the steering handle. The degree of opening of the throttle valve can be adjusted by rotating the grip. The speed of the engine changes as a result. The boat pilot simultaneously performs two operations with one hand; that is, rotates the grip to adjust the degree of opening of the throttle valve while holding the grip to steer.
In the case of trawling (trawl fishing) and the like, the speed of the vessel is finely adjusted according to conditions. There is therefore a need for the ability to finely adjust the speed of the engine. Finely adjusting the engine speed while steering the vessel for a long period of time places a significant burden on the boat pilot, and requires that the pilot have experience. A significant amount of training is needed, particularly for a novice to be able to easily pilot the vessel.
The outboard motors described above are therefore provided with a separate operating member for fine adjustment at low speed. However, since the separate operating member is finely adjusted by a mechanical structure, the structure is complex, and there is potential for further improvement thereof.
The outboard motor disclosed in Japanese Patent Application Laid-Open Publication No. 2006-205789 (JP 2006-205789 A) also has a rotatable grip at the distal end of the steering handle. The degree of opening of the throttle valve can be adjusted by rotating the grip. The speed of the engine changes as a result. The boat pilot simultaneously performs two operations with one hand; that is, rotates the grip to adjust the degree of opening of the throttle valve while holding the grip to steer. Experience is required for the boat pilot to be able to hold the engine speed constant while steering the boat for long periods of time.
The outboard motor disclosed in JP 2006-205789 A is therefore provided with a mechanical handle adjustment mechanism so that the grip does not rotate during steering. As a result, it is relatively easy to keep the speed of the engine constant. However, since a mechanical structure prevents the grip from rotating, the structure is complex, and there is potential for further improvement thereof.